Tangential separating device for solid matter

ABSTRACT

The invention relates to a device and a method for chemically and physically separating solid materials from a suspension using flotation. A rotationally symmetrical flocculation/flow reactor is provided with outlets in the lower part thereof and is arranged in a separating tank. At least one suspension inlet extends eccentrically into said reactor. The supplied suspension is guided into said reactor. The supplied suspension is guided into the upper area of the flocculation reactor via the suspension inlet. A circular flow is thus created which drains off from the flocculation reactor downwards in a tangential and radial manner over the outer circumference into circularly arranged distribution cells which reinforce the tangential component of the suspension flow when said flow is delivered into the separating tank. In prior art, the flow of the mixture consisting of the suspension and air-sacs extends radially outwards. One advantage of the invention is that said flow of the mixture has to travel a longer way to the outlets in the area of the wall of the tank due to the tangential flow component. The solid matter can be separated more effectively by virtue of the longer travel path or the longer presence in the separating tank.

The invention relates to a device and a method for the physicalseparation of solid matter from suspensions using the flotation methodin an essentially cylindrical separating tank. Devices of this type are,for example, known from EP-A-0 442 463 or WO 95/23027.

Based on these previously known devices or methods, the object of thepresent invention is to further improve the degree of separation in theseparation of solid matter of generic devices and methods.

A rotationally symmetrical flocculation reactor, closed at the top andwhich preferably expands downward in its diameter, is arranged centrallyin the middle in the cylindrical separating tank.

The suspension inlet does not take place concentrically in theflocculation reactor but preferably via a vertical inlet pipe, theeccentrical supply and the inlet pipe, preferably open on one end,resulting in the formation of a gentle, downward-directed anddecelerating circulation flow which decisively promotes the flocculationprocess required for the separation of solid matter by flotation. Anoverflow edge, situated on the periphery and enabling the suspension toflow out of the flocculation reactor, is found at the lower end of therotationally symmetrical flocculation reactor.

The liquid/suspension flowing out of the flocculation reactor flows intodistribution cells situated on the outer periphery of the flocculationreactor, said distribution cells having a geometrical form such that atangentially directed flow into the separating tank results at the endof the distribution cells, i.e. an inlet angle that also has, inaddition to the radially directed flow component, a tangential flowcomponent.

A pressure-release inlet is arranged in the flocculation/flow reactor inwhich the release pressure of a liquid oversaturated with gas can bereduced via an annular aperture. The bubbles resulting from the excessgas form a carpet of bubbles which flows radially outward from thepressure-release inlet in an almost horizontal direction, comes to liebeneath the gentle, downward-directed decelerating circulationsuspension flow resulting in the flocculation/flow reactor and/or mixeswith it. As a result of the adjustable annular aperture of thepressure-release inlet, an operation at various release pressures ispossible which enables an optimum control of the bubble sizes that isdependent on the absolute level of the release pressure.

The solid floccules resulting in the circular flow of theflocculation/flow reactor are thus optimally underlaid or mixed with abubble carpet and tangentially introduced into the separating tank viathe distribution cells disposed on the outer periphery of theflocculation reactor.

In a preferred embodiment, the distribution cells are formed in such away that the tangential components of the direction of flow are largerthan the radial components. Even more preferable, the ratio of thetangential components to the radial components is 1:1 to 50:1,especially preferred 2:1 to 5:1.

In order to use flotation more successfully as chemical and physicalseparating methods, an optimal formation of solid floccules/solid bondsis an essential prerequisite for obtaining good separation results,whereby the use of chemical flocculation adjuvants (e.g. polymers) areprior art nowadays, however, the costs of these flocculation adjuvantsrepresent a considerable operating cost factor.

The use of flocculation adjuvants or solid flocculation can beconsiderably optimized thereby that the flocculation itself takes placein its own reaction chamber at defined, non-turbulent flow conditionswhile maintaining specific, even the shortest reaction times. This wasnot taken into consideration in the previous prior art.

The present invention optimally meets these requirements for an improvedflocculation and enables the reduced use of flocculation adjuvants withthe flocculation/flow reactor in which a gentle downward-directedcirculation flow is produced by the eccentric inflow.

In the previous prior art, the mixing of the bubbles produced byoversaturation mostly takes place in pipes or narrow flow chambers athigh flow velocities of about 1.6 to 3 m/s, in addition, the paths fromthe bubble formation until mixing and to the start of the effectiveflotation are long (3 to 10 m). Both factors result in disadvantages;high flow velocities and long paths destroy formed floccules orinhibit/prevent flocculation, the smallest bubbles produced byoversaturation coalesce to form larger bubbles which are less effectivefor flotation.

On the other hand, in the present invention, the bubbles are gentlymixed in without affecting the floccules in the flocculation/flowreactor at reduced velocity, short paths of preferably 0.5 to 1 m up tothe separating tank in which the flotation takes place, preventcoalescence of the bubbles and enable improved flotation with thesmallest bubbles.

A further advantage of the invention lies therein that the flow of themixture consisting of suspension and air bubbles that is usuallydirected purely radially outward must travel a longer path to the outletopenings in the area of the tank wall due to the tangential flowcomponent than in conventional separating methods with purely radialflow, so that the separation of solid matter is carried out in a moreeffective manner due to the longer paths or the longer stay in theseparating tank. In addition, the flow-off is also calmer which alsoresults in an improved separation. Thus, the device of the invention canbe configured more compact vis-a-vis previously known designs.

A preferred further embodiment of the invention provides that thepressure-release inlet comprises an axially movable, preferably conicaladjusting piston, a more or less narrower annular aperture being formedby its axial adjustment, the liquid mixed with the released gas passingthrough said annular aperture under the sudden fall in pressure. Byadjusting the aperture, depending on the desired flow throughput, thefall in pressure can be set in such a way that a suitable bubble sizeresults which is advantageously between 10 μm and 1500 μm.

An advantageous further embodiment of the invention provides thatdeflecting devices be provided above the pressure-release inlet whichserve to bundle the flow of the bubble-added liquid in horizontal/radialdirection, so that a two-layer flow is formed, the bubble-added liquidrunning at the bottom of the tank and the suspension flow above it.

As soon as the liquid freed of solid material reaches the area of theouter wall of the separating tank, it is removed from the separatingtank via specially designed outlet openings and conveyed to a liquidoutlet via collecting pipes. Preferably, the outlet openings areconfigured in a slot-shaped manner, these slots being located over theentire periphery of the wall of the tank above the floor. These outletopenings are brought together in groups by suitable channels or linesand communicate with a number (preferably 4) of outlets distributedalong the periphery of the tank.

An arrangement to be provided alternatively or in addition for drainingthe clarified liquid lies therein that at least one surroundingdischarge pipe is situated on the outer wall of the separating tankabove the base of the tank and provided with a plurality of outletports. Preferably, these outlet ports are situated in the lower area ofthe discharge pipes, so that the inlet into the discharge pipe takesplace from the bottom, in order to effectively prevent sinkingsubstances from blocking the openings. This discharge pipe communicatesvia a connecting line with an outlet. Alternatively, it is also possibleto divide this discharge pipe into several, preferably 3-4 dischargepipe sections, which together produce a complete ring and eachcommunicate with their own outlets. Especially simple from a technicalpoint of view, the discharge pipes may be realized if they consist ofstraight pipe pieces connected to one another and, in this way, form atype of polygonal discharge pipe.

According to a further advantageous embodiment of the invention, arotating sludge removal device is provided above the separating tankwhich preferably comprises at least two sludge paddles which both turnabout their own common axis of rotation inclined slightly to thehorizontal and about the vertical axis of the separating tank.

An especially preferred further embodiment of the invention providesthat the direction of rotation of the sludge-removal device travelsopposite to the tangential component of the flow of the suspension, as aresult of which the relative velocity is increased between the sludgepaddles and the sludge flow in the upper area of the filled tank whichleads to an improved and more effective discharge, in particular of thesolid fibers contained in the suspension.

An especially effective removal of the sludge can be obtained with afurther embodiment according to the invention in which several scoopingdevices are provided which are distributed about the periphery of arotating shaft and which convey the sludge in a discharge outletextending parallel to the shaft, each scooping device consisting of abow-like blade and a sludge paddle. The sludge is cut into by means ofthe bow blade, preferably configured rectangular, and the removal of theloosened sludge thus facilitated by the following sludge paddle. Thisfurther embodiment has special advantages with heavily packed, encrustedor otherwise hardened sludge formations.

In a simple embodiment, the base of the separating tank can beconfigured flat. A preferred alternative embodiment of the inventionprovides that the base is configured in an annular channel-like mannerand comprises at least one sediment outlet, as a result of which heavyparts deposited during the separating process can be effectivelyremoved.

The aforementioned embodiments of the invention produce a separation ofthe suspension on the flotation principle. Alternatively, it is alsopossible to carry out a separation on the sedimentation principle,whereby especially the introduction of a liquid mixed with gas isomitted, i.e. only a suspension inlet is provided for introducing thesuspension to be freed from solid matter, it being possible to conveythis suspension through the separating tank in the same way as in theembodiments described above through the eccentric arrangement of thesuspension inlet with a tangential velocity component.

The invention shall be described in greater detail in the following withreference to the attached drawings, showing:

FIG. 1: a schematic vertical cross section through a separating devicefor solid matter according to the invention;

FIG. 2: a schematic top view onto the device of FIG. 1;

FIG. 3: a representation of the central area of a separating device forsolid matter similar to the one of FIG. 1, in cross section;

FIG. 4 a schematic top view onto the device of FIG. 3;

FIG. 5 a preferred embodiment of a liquid outlet device in a top view;

FIG. 6 a perspective detail view of the embodiment of FIG. 5;

FIG. 7 a schematic detail view of an alternative liquid outlet device;

FIG. 8 a schematic top view onto a sludge-removal device in a solidmatter separating device according to the invention;

FIG. 9 a schematic side view of the sludge-removal device of FIG. 8;

FIG. 10 four schematic representations regarding the operating mode ofan embodiment of a sludge-removal device, and

FIG. 11 three views of an alternative embodiment of a sludge-removaldevice.

The invention shall now be described in greater detail with reference toFIGS. 1 and 2 and/or 3 and 4, respectively. The same reference numbersin the various representations identify the same parts.

The separating device 10 according to the invention, shown in FIGS. 1and 2, essentially consists of a cylindrical separating tank 12 in thecentral axial area of which a central structural unit 14 is arranged.This central structural unit 14 comprises a flotation-collecting tank16, open at the top, which is connected with a flotation dischargeoutlet 18 as shown in FIGS. 3 and 4. A rotationally symmetricalflocculation reactor 20 is situated underneath the flotation collectingtank 16, said flocculation reactor 20 being closed at the top and on theside and only having horizontal openings in the bottom or a radialperipheral opening below a peripheral edge 22. The flocculation-reactor20 is configured conically in the embodiment shown in FIG. 1 andcylindrically in the embodiment shown in FIG. 3.

A suspension inlet 24 opens into the upper area of the interior of theflocculation reactor 20, the opening 26 of said inlet 24 beingconfigured diagonally, whereby the angle of inclinaton is at a rightangle to the line of tilt 28 shown in FIG. 4.

In the embodiment shown in FIGS. 3 and 4, a pressure-release inlet 32 isprovided in the bottom area 30 of the flocculation reactor 20, the inletaperture of said pressure-release inlet 32 can be adjusted by a conicaladjusting piston 34. This adjusting piston 34 is set via am adjustingrod 36 and a hand wheel 38 in the embodiment shown. Of course, in analternative, it is also possible to adjust the adjusting piston 34 in amotor-driven manner.

In the embodiment shown, the adjusting piston 34 has a substantiallylarger diameter than the pressure-release inlet 32, as a result, itforms a deflecting edge 35 the purpose of which is to divert thebubble-loaded liquid flowing in via the pressure-release inlet 32 inhorizontally radial direction and to prevent a too premature mixing withthe suspension flow coming from the top. Alternatively, the adjustingpiston 34 can also be made with a smaller diameter and a firmly mountedplate-like baffle can be provided above the adjusting piston 34.

The pressure-release inlet 32 is supplied by a liquid pipe 40 via whicha liquid mixed with a released gas is fed. Radially outside of theperipheral edge 22, a number of distribution cells 44 extend adjacent toone another, preferably each having a rectangular flow cross section,which expands radially outward from the flocculation reactor 20 inperipheral direction and vertical direction.

The distribution cells 44 form a channel, curving increasingly inperipheral direction, and are separated from one another by separatingwalls 46. The number and curvature of the distribution cells 44 isselected in such a way that a desired flow outlet angle of thesuspension/bubble mixture is produced which comprises a significanttangential component, i.e. it does not run completely radial. It isagain expressly noted that the conically truncated configuration of theflocculation reactor 20, as shown in FIG. 1, or the bell-shapedconfiguration noted in the claims, also in the embodiment of FIGS. 3 and4, can be used with a pressure-release inlet 32.

The function of the device of the invention according to FIGS. 1 and 2is as follows:

A suspension mixed with solid matter (for example, small heavy parts,fibers and other components) is supplied via the suspension inlet 24,said suspension entering the reactor chamber in tangential direction (asindicated by arrow S in FIG. 4) due to the fact that the outlet opening26 of the suspension inlet 24 is inclined and travels spirally downwardin the flocculation reactor 20. The suspension can then flow radiallyoutward into the distribution cells 44 after passing the peripheral edge22, the already existing rotary movement (velocity component intangential direction) thereby being intensified by the distributioncells 44. As can be seen especially in FIGS. 1 and 2, the mixtureleaving the central structural unit 14 then flows outward at a definedangle to the radial direction, as is indicated by arrow A in FIG. 2.

In this embodiment, a liquid oversaturated with gas is preferablysupplied to the suspension before it is introduced via the suspensioninlet 24, so that micro bubbles have formed in the mixture to which thesolid matter particles to be separated adhere and cause them to float onthe liquid surface in the separating tank 12. At the same time, heavysubstances can sink to the bottom of the tank 30 where they are removedby removal devices (sediment removers) (not shown) or reach suitablecollecting channels. The clarified liquid is then drained off in thearea of the outer wall of the separating tank 12, which will bedescribed in greater detail in the following with reference to FIGS.5-7.

The alternative embodiment shown in FIGS. 3 and 4 functions in a verysimilar manner as described above, with the exception that a gas-mixed(preferably saturated) liquid such as water is introduced separatelyfrom the suspension via the liquid inlet 40, said liquid being releasedwhen passing the pressure-release inlet 32, so that micro bubbles 52form. With increased mixing, the suspension flow and the bubble flowcoming from the upper area of the reaction container 20, already mixedin the direction of peripheral rotation, pass outward throught hedistribution cells 44.

As a result of the embodiment according to the invention, a velocitycomponent is conveyed in peripheral or tangential direction to themixture flowing essentially radially outward and consisting ofsuspension and small bubbles, as a result of which the path covered byflowing through the separating tank 12 is considerably longer comparedto a conventional entirely radial flow and an improved degree ofseparation can be obtained which could only be attained with largerseparating tanks or a smaller throughput in conventional devices. Thus,the embodiment according to the invention also enables a more compactstructure of the separating device for solid matter.

As shown in FIGS. 5-7, the clarified liquid is removed from the tank inthe area of the outer wall 54 of the separating tank 12. In FIGS. 5 and6, a preferred embodiment of this inventive idea is thereby shown inwhich the clarified liquid discharges through three outlet pipes 56 a,56 b and 56 c. These outlet pipes 56 consist of individual straight pipesections and each extend over about one-third of the entire periphery ofthe tank wall 54. Of course, more or fewer pipes can also be provided,as long as the liquid is discharged over the entire periphery. Each ofthe outlet pipes 56 is connected with a clean water outlet 58. As can beseen in FIG. 6, the outlet pipes 56 have a plurality of small openings60 in their base area via which the clarified liquid can enter into theoutlet pipes 56. By arranging the openings 60 in the base area of theoutlet pipes, it is prevented that they are blocked by solid matter orparticles perhaps falling from the top.

An alternative embodiment of the outlet device for the clarified liquidis shown in FIG. 7, in which opening slots and/or boreholes 62 areprovided in the tank wall 54 in the vicinity of the base 30 over theentire periphery, said openings and/or boreholes 62 opening into acollecting line 64 from where the clarified liquid is supplied to one ormore clean water outlets 58.

A first embodiment of a sludge-removal device 66 a rotating above theseparating tank 12 about the vertical central axis of the separatingtank 12 is shown in FIGS. 8 to 10. The retaining structure for thesludge-removal device 66 a is not shown for reasons of clarity. Thissludge-removal device 66 a consists essentially of an axis of rotation68 extending radially vis-à-vis the central axis of the separating tank12 and to which at least two sludge paddles 70 a, 70 b are fastened. Theaxis of rotation 68 with the two paddles 70 is turned about the axis ofrotation 68 via a rotational drive 72 and the entire sludge-removaldevice 66 a is simultaneously moved by means of a rotary drive 74 in thedirection indicated by arrow U, i.e. clockwise, about the central axisof the separating tank 12. This direction of rotation U is, according tothe invention, opposite the movement of rotation of thesuspension/bubble mixture indicated by arrow A.

As shown in FIG. 10 with reference to four different positions of thesludge-removal device 66 a, the sludge paddles 70 a and 70 b scoop thesludge 78 that has formed on the surface of the liquid 76 off, conveythe scooped sludge 80 during the further rotary movement in direction ofthe axis of rotation 68 which is inclined vis-à-vis the horizontal tothe central axis of the separating tank 12 (as shown in FIG. 9). Thescooped sludge 80 falls onto the flotation collecting tank 16, shown inFIGS. 1 and 3, and is then discharged via the flotation discharge pipe18.

Of special significance for an especially effective scooping of thesludge 78, in particular if it contains fibre particles, is the factthat the rotary movement U of the sludge-removal device 66 a is oppositeto the movement of the suspension/bubble mixture A, shown in FIGS. 8 and10, to increase the relative velocity between the sludge 78 to bescooped off and the sludge paddles 70.

A liquid which is under increased pressure and thereby mixed with gas issimultaneously introduced into the mixing chamber below the peripheraledge 22 via the liquid line 40 and the pressure-release inlet 32. Asudden decrease in pressure is produced in the supplied liquid in theaperture in the pressure-release inlet 32 formed by the adjusting piston34, as a result of which the gas released in the liquid (to the extentthat it exceeds the saturation capacity at the pressure prevailing inthe bottom of the tank) flows out as micro bubbles 52 of preferablyabout 10 μm to 1500 μm. The adjusting piston 34 can thereby be adjustedaxially as required by means of the hand wheel 38 in order to obtain adesired bubble formation dependent on the desired throughput of theliquid supplied via the liquid line 40 while interacting with theincreased pressure in the liquid line 40. The liquid mixed with microbubbles thereby mixes with the suspension being added from the upperarea of the flocculation reactor 20, whereby this mixture passes throughthe flow channel 44, as indicated by arrow K.

To obtain as uniformly decelerating a flow as possible and also toproduce as slight unsteadinesses and turbulances as possible during thetransition from the flow channel 44 into the main area of the separatingtank 12, the height of the flow channel 44 increases steadily radiallyoutward, preferably in a linear manner.

Three configurations of a second embodiment of a sludge-removal device66 b are shown in FIGS. 11a, 11 b and 11 c. This sludge-removal device66 b, also rotating in the same way as in FIG. 8 above the separatingtank 12, has a preferably horizontal axis of rotation 82 which is drivenby means of a rotary drive 72. This sludge-removal device 66 b comprisesseveral sludge paddles 70 c distributed on the periphery of the axis ofrotation 82 and a number of bow blades 84 also distributed on theperiphery which have a cutting area 86 extending parallel to the axis ofrotation 82 and also have tie rods 88 a, 88 b at both ends for holdingthe cutting area 86. In the embodiment shown, 6 sludge paddles 70 c and3 bow blades 84 are provided. A ramp 90 and outlet channel 92 arearranged in such a way that the sludge paddles 70 c can convey thesludge to be discharged into the outlet channel 92, from where it isconveyed by means of a screw conveyor 94 radially inward into theflotation collecting tank 16. In this embodiment, the axis of rotation82 turns in the direction indicated by arrow D, whereby the bow blades84 dip into the sludge 78 and separate parts from it which can be pickedup by the following sludge paddles 70 c and transported onto the ramp90, after passing it, the separated sludge falls into the outlet channel92. The sludge paddles 70 c thereby preferably have a curvature 96directed opposite the direction of rotation D in order to convey thesludge from the ramp 90 completely into the outlet channel 92. Duringthis scooping-off process, the sludge-removal device 66 b turns in thedirection of rotation indicated by arrow U in FIG. 11c.

What is claimed is:
 1. A device for the chemical and physical separationof solid matter, from a suspension, comprising an essentiallycylindrical separating tank, in which centrally a rotationallysymmetrical flocculation/flow reactor is provided into which at leastone suspension inlet directs flow eccentrically, said suspension inletconducting the supplied suspension into the flocculation reactor andthereby creating a circular flow, wherein the suspension inlet isprovided in an upper area of the flocculation reactor and the circularflow drains off from the flocculation reactor downward with tangentialand radial components over an outer periphery into circularly arrangeddistribution cells configured and dimensioned to reinforce thetangential component of the suspension flow when said flow is deliveredinto the separating tank.
 2. The device according to claim 1, whereinthe flocculation reactor is configured in a bell-shaped, cylindrical orconically truncated manner and the suspension inlet is situated above anoutlet opening.
 3. The device according to claim 1, wherein apressure-release inlet with an annular aperture, via which the releasepressure is decreased, is arranged in a base area of the flocculationreactor.
 4. The device according to claim 3, wherein a plate-like baffleis provided above the pressure-release inlet.
 5. The device according toclaim 3, wherein the annular aperture is adjustable, by means of anaxially movable adjusting piston, on which a deflecting edge is moldedto deflect an emerging flow of bubbles in a horizontal direction.
 6. Thedevice according to claim 1, wherein the distribution cells have flowchannels with a radially outward increasing cross section.
 7. The deviceaccording to claim 6, wherein the distribution cells have side wallswith an inlet and an outlet, the side walls of the distribution cells,as seen from above, having a cycloidal curvature and a larger tangentialcomponent at the outlet than at the inlet.
 8. The device according toclaim 6 or 7, wherein a ratio of the tangential component to the radialcomponent of the suspension flow velocity at the distribution cell inletis between 0.3:1 and 1:1.
 9. The device according to claim 8, whereinsaid ratio at the cell inlet is between 0.8:1 and 1:1.
 10. The deviceaccording to claim 6 or 7, wherein a ratio of the tangential componentto the radial component of the suspension flow velocity at thedistribution cell outlet is between 1:1 and 50:1.
 11. The deviceaccording to claim 10, wherein said ratio at the cell outlet is between2.5:1 and 5:1.
 12. The device according to claim 6, wherein the heightof the distribution cells increases steadily radially outward.
 13. Thedevice according to claim 6, wherein 3 to 10 distribution cells areprovided.
 14. The device according to claim 1, wherein the at least onesuspension inlet comprises devices for obtaining a tangential outflow ofthe suspension in the reactor interior.
 15. The device according toclaim 14, wherein the suspension inlet has an inclined end edge and/or acurvature or a deflecting vane in the end area in tangential direction.16. The device according to claim 1, wherein a plurality of spacedoutlet openings are provided in the outer wall of the separating tankwhich communicate via collecting lines with at least one outlet.
 17. Thedevice according to claim 1, wherein the outlet openings are configuredslot-like and communicate in groups with 2 to 8, outlets distributedalong the periphery of the tank.
 18. The device according to claim 1,wherein at least one rotating outlet pipe with a plurality of spacedopenings is fastened on the inside to the outer wall of the separatingtank, the outlet pipe communicating via a connecting line with anoutlet.
 19. The device according to claim 18, wherein between 2 and 8,drain pipe sections are provided adjacent to one another and distributedon the periphery, which each communicate via at least one connectingline with their own outlet each.
 20. The device according to claim 18 or19, wherein a drain pipe or drain pipe section consists of severalstraight pipe pieces connected to one another.
 21. The device accordingto claim 1, further comprising at least one sludge-removal devicerotating above the separating tank.
 22. The device according to claim21, wherein the sludge-removal device comprises two sludge paddles, thedirection of movement of which, at the immersed moment, is opposite tothe tangential component of the suspension flow.
 23. The deviceaccording to claim 21, wherein the sludge-removal device has a firstnumber of sludge paddles distributed around a rotating shaft and asecond number of bow-like blades distributed around the shaft whichseparate sludge to be removed from the rest of the sludge and convey itinto an outlet channel extending parallel to the shaft.
 24. The deviceaccording to claim 23, wherein a screw conveyor is provided in theoutlet channel.
 25. The device according to claim 23, wherein the sludgepaddles have a bend in the radial centre extending counter to thedirection of rotation.
 26. The device according to claim 1, wherein thebase of the separating tank is configured in an annular channel-likemanner and comprises at least one sediment discharge opening.
 27. Thedevice according to claim 1, wherein separation is based on asedimentation principle.
 28. A device for separation of solid matterfrom a suspension, comprising: a separating tank; a rotationallysymmetrical flocculation/flow reactor disposed centrally in said tankand defining openings along a bottom surface; a suspension inletdisposed in an upper portion of said reactor and positioned to create acircular flow in said reactor; and a plurality of distribution cellsdisposed below the reactor to define flow channels having a radiallyoutward increasing cross section, said channels having side walls, aninlet communicating with said openings and an outlet communicating withsaid separating tank.
 29. The device according to claim 28, furthercomprising: a flotation collecting tank disposed above theflocculation/flow reactor; and a flotation discharge outletcommunicating with said collecting tank and extending to a positionoutside said separating tank.
 30. The device according to claim 29,further comprising a pressure release inlet disposed in said separatingtank below the flocculation/flow reactor.
 31. The device of claim 29,further comprising peripheral drainage means disposed around a lowerportion of said separation tank.
 32. The device according to claim 29,further comprising a sludge removal device disposed for rotation aroundan upper portion of said separating tank and cooperating with saidcollecting tank for collecting sludge therein.